��Where does your water come from?

Water Fluency for Journalists

Via Zoom

July 29, 2021

Dr. Gigi A. Richard

garichard@fortlewis.edu

Land (and Watershed) Acknowledgement

• At Fort Lewis College, we begin all events by acknowledging that the land of the San Juan River Watershed is the ancestral lands and territories of the Nuchu (Ute), Apache, Pueblos, Hopi, Zuni, and the Diné (Navajo) Nation. These tribal nations are the traditional stewards of the land and water, and we would like to honor these tribes by providing this acknowledgment. We believe it is important to provide this recognition because the narratives of this land and region have long been told from one dominant perspective, without full acknowledgment of the Indigenous peoples who lived on this land since time immemorial and long before it was Silverton, Durango, Aztec, Farmington, and the Animas River as they are known today.

What is the “Water Year”?

Oct 1

2020

Sept 30

2021

2020

2021

Baseflow

Peak Flow

Snow Water Equivalent (SWE)

Streamflow

Water Year 2021

Where does our water come from?

Grand Junction

≈ 9 in/yr

Colorado Average Precipitation ≈ 15.5 in/yr

Boulder ≈ 21 in/yr

Denver ≈ 16 in/yr

Fort Collins ≈ 16 in/yr

Steamboat Springs

• 24 in/yr

Av. Annual snowfall 167 in.

Average precip data from wrcc.dri.edu

Wolf Creek Pass 1E

(Elev 10,640’)

Avg total precip: 45 in

Avg annual snowfall: 436 in

(Period of Record : 1956-2001)

Colorado is a ‘headwaters’ state

Rangely

≈ 10 in/yr

Av. Annual snowfall 29 in.

Image credit: Colo. Foundation for Water Education

Colorado is a ‘headwaters’ state

Colorado River Basin

34% of watershed receives < 10 in/yr

Most of the runoff is produced by only 15% of the drainage area

84% of watershed receives < 20 in/yr

4 Key Basins – Upper Colo, Gunnison, Yampa & San Juan produce 55% of all runoff

Map by Gigi Richard

Precipitation data from National Atlas

Up to 80% from snowmelt

Mountain snowpack…

is Colorado’s water tower

Snowmelt Process

snowpack

streamflow

Snowmelt and streamflow generation are complex processes with many interconnected influencing factors

Snow melts mainly from the top down

• Solar radiation
• Air temperature
• Wind

groundwater

soil water

snowpack

streamflow

snowpack

infiltration

streamflow

sublimation

runoff

groundwater flow

streamflow

snowpack

infiltration

streamflow

sublimation

runoff

groundwater flow

Other factors…

dust on snow

streamflow

snowpack

Yampa River Drainage Basin near Maybell

3,380 mi²

Columbine SNOTEL 9,160 ft.

“…we [Colorado] haven't had a cooler than average month since Apr 2020, or a wetter than average month since Feb 2020!”

Colorado Climate Center, January 2021 Climate Summary

From Brad Udall, CSU, October 2020

From Russ Schumacher, Colorado Climate Center�presentation at Colorado Water Congress, Feb. 4, 2021

WY 2021

Variability in timing and distribution of precipitation result in variable streamflow and availability of surface water supply

What do warmer temperatures mean for Colorado’s snowpack?

Trend in April 1^st water content of snow

From Mote, P.W., Li, S., Lettenmaier, D.P. et al. Dramatic declines in snowpack in the western US. �npj Clim Atmos Sci 1, 2 (2018). https://doi.org/10.1038/s41612-018-0012-1

Declining trend of the April 1^st water content of snow in SNOTEL regions during the 1978–2007 water years

Clow, D.W., 2010. Changes in the timing of snowmelt and streamflow in Colorado: a response to recent warming. 

Journal of Climate,.

699 snow course locations,

1955-2016, red circles = negative trend, blue circles = positive trends

modeling results

As Temperature ↑ Evaporation will ↑

Annual Evaporation

~600,000 ac-ft/yr

Lake Powell

Crop transpiration ↑

​

Evaporation from soils ↑

​

Irrigation ↑

​

Streamflow ↓

Crausbay et al. 2020, One Earth

New types of drought?

100% of Colorado in Drought

“Water Managers understand the problems but we are far from solutions” �– Brad Udall, CSU, Oct 2020

Is this the “New Normal”?

Aridification?

Take-home thoughts

• Colorado’s snowpack = Colorado’s water supply
• Temperature matters

Dr. Gigi A. Richard

garichard@fortlewis.edu